RKK
- Kagoshima
- R2K
- RK (disambiguation)
- RK2 plasmid
- RKK Energia
- RKK Kumamoto Broadcasting
- RRK (disambiguation)
- Reichskommissariat Kaukasien
- Reichskulturkammer
- Revi Karuna Karan
- Revi Karunakaran Memorial Museum
- Ring Ka King
- Risshō Kōsei Kai
- Robert Kenneth Kraft
- Rooms-Katholiek Kerkgenootschap
- Rotterdamse Kunstkring
- Runda Kumpulan Kecil
- Sweet Scent of Service